The invention relates generally to systems and methods for electrical power transmission and, more particularly, to systems and methods for electrical power transmission using a direct current (DC) cable.
Alternating current (AC) transmission systems may be inefficient for transmitting high voltage power over long distances as capacitance in an AC cable reduces the load carrying capability of the AC cable. In contrast, DC transmission may provide a more efficient way to transmit high voltage power over long distances. Medium voltage (MV) and high voltage (HV) DC are two commonly used long distance transmission DC systems across various applications such as, for example, subsea processing for oil and gas industry and offshore wind power production.
There is a growing need to deliver power from onshore or offshore platforms to electrical loads at seabeds or remote offshore locations. However, conventional HVDC systems may not be well suited for sub-sea installations due to the size and high number of components involved.
Further, long distance transmission such as that used for sub-sea power transmission may be achieved via sub-sea cables that carry the power from a power source such as a DC source or an AC source to one or more offshore power stations and substations. However, with increasing cable length, the probability of a cable fault may increase. Repairing sub-sea cables may require a long time, for example, several weeks. In the meantime, the fault in the cable may affect the power supply to the power station/substation to which the faulty cable is connected.
Thus, there is a need to provide a power transmission system that is less expensive, reliable, and fully operational even in the case of a cable fault. Further, there is a need to provide a power transmission system in which the faulty cable may be repaired or replaced while the power transmission system is in operation.